Eἰς ἰδιότητα is a common expression among scholiasts, meaning "for its being a proper noun," lit. "for purposes of specifying individuality." Usually it pertains to an accent or breathing mark being changed when a common noun or adjective becomes someone's or something's name. For example, Stephanus of Byzantium (10th cent. grammarian) writes of Menander's play Thettalē (The Thessalian Woman), "The name of Menander's drama Thettalē is accented on the final syllable in the Attic dialect, which is done for its being a proper name" (τὸ Θεττάλη δρᾶμα Μενάνδρου βαρύνεται παρὰ Ἀττικοῖς, εἰς ἰδιότητα τεθέν: Ethnica, Ed. Meineke, p. 311.2).